Thanks for all of the input guys
Some good sugestions there.
I can get ERW round tube localy but stainless & alu coated steel is a bit of a problem.
There is a stockist of stainless in Falmouth ( 20 miles'ish ) but his prices are steep to say the least
Not even sure what grade of stainless is commonly used for exhaust components
The whole idea might end up as pie in the sky but kinda thinking of taking a trip up to see Matt at Stakesy's for a demo of the Pro-tools tube bender.
Here's a linky for anyone interested in having a gander.
Pro-Tools Tube Bender
I have had a look at the video clip & it doesn't look to deform the tube too much.
Obviously if it deforms the tube badly then it will be no good for on show, exterior exhaust components
